The invention generally relates to a technique and apparatus to deploy a cement plug in a well.
A cement plug may be deployed in a subterranean oil or gas well for a variety of different reasons. For example, a cement plug may be placed in the well to seal off a lost circulation zone, kick off a side track or initiate directional drilling. Additionally, a cement plug may be set in the well to temporarily seal and protect a formation or seal the well for abandonment.
Plug cementing typically includes communicating a predetermined amount of cement slurry into a wellbore through a drill string and allowing the cement slurry to set. Mechanical or fluid spacers may be pumped before and after the cement slurry through the drill string for purposes of isolating the cement slurry from drilling fluid. Uncertainties associated with the plug cementing operation, such as imprecise knowledge of the volume of cement slurry pumped and the exact wellbore volume into which the cement slurry is pumped, may adversely affect the plug cementing operation and the quality of the plug.